The invention relates to a method of manufacturing a semiconductor device, in which a titanium disilicide layer is formed on a substrate by means of a chemical reaction activated by plasma from the gaseous phase.
A method of the kind mentioned in the opening paragraph is known from U.S. Pat. No. 4,557,943. In the known method, use is made of a gaseous phase comprising gaseous silane and gaseous titanium tetrachloride, while a titanium disilicide layer is deposited on the substrate.
Examinations which have led to the invention have proved that the composition of the deposited titanium silicide layer can strongly depend upon the ratio of the quantities of the silane and titanium tetrachloride present in the gaseous phase. It has more particularly proved to be extremely difficult to deposit by means of a gas plasma a titanium disilicide layer on a substrate with comparatively small variations around a gaseous phase composition comprising about 1 part of TiCl.sub.4 for 8 parts of SiH.sub.4, in which event normal titanium disilicide (TiSi.sub.2) is deposited, for example, a layer having a composition with about 3 parts of Ti for 4 parts of Si may readily be deposited.
It has also been found that with a gaseous phase comparatively rich in titanium, titanium silicide layers are deposited, which are comparatively rich in titanium, the composition of the deposited layer being only slightly dependent upon the composition of the gaseous phase.